In general, a transmitting stage or a receiving stage of a semiconductor integrated circuit is connected to a termination resistor having the same resistance as an impedance of a transmission channel. The termination resistor may match the impedance of the transmission channel with the impedance of the transmitting or receiving stage to suppress reflection of signals (including data) transmitted through the transmission channel.
In integrated circuits such as central processing units (CPUs) and/or graphic memory devices having a relatively smaller power consumption constraint, the termination resistor electrically connected to the receiving stage has been widely employed to effectively suppress the signal reflection. However, in the event that the termination resistor is electrically connected to the receiving stage, a direct current (DC) always flows through the termination resistor, drawing high power consumption. Thus, it may be difficult to use the design scheme employing the termination resistor connected to the receiving stage in some integrated circuits such as mobile devices or systems having a relatively greater power consumption constraint. Accordingly, the integrated circuits of the mobile devices or systems employ a design scheme where the termination resistor is connected to the transmitting stage.
The design scheme having the termination resistor connected to the transmitting stage may be realized using a signal transmission circuit. More specifically, the integrated circuits may include the signal transmission circuit that is connected to the transmitting stage to transmit the signals through the transmission channel so that the impedance of the signal transmission channel may be matched by controlling an electrical resistance of the signal transmission circuit. The signal transmission circuit may include a plurality of drivers for driving the signals transmitted through the transmission channel. The electrical resistance of the signal transmission circuit may be adjusted or controlled by selectively turning on at least one of the plurality of drivers.